Inclusion of chitosan in Tenebrio molitor larva protein hydrogels improved the rheological and gel properties of the composite hydrogels

Tenebrio molitor protein (TMP) is a highly promising alternative protein resource. However, hydrogels formed from TMP alone typically exhibit fragility and brittleness, limiting their development and application. This study investigated the effects of varying chitosan (CS) concentrations on the mechanical properties of TMP hydrogels. We found that CS concentrations between 0.5 and 1.5 % greatly improved the mechanical properties, water-holding capacity (WHC), and rheological properties of the TMP/CS composite gels. Specifically, the incorporation of 1.5 % CS improved the storage modulus of the gel, enhanced the interaction between water and proteins, and yielded a WHC of 53.32 %. Furthermore, the addition of 1.5 % CS altered the secondary structure and spatial conformation of the protein, with a β-folding content of 43.27 %, leading to a significant enhancement of hydrophobic interactions and hydrogen bonding in the composite gel system and the formation of a dense and stable gel network structure. However, the addition of excessive CS (2.0 % ~ 3.0 %) led to phase separation of the gel system, which decreased gel strength and increased the viscosity of composite gels. In conclusion, optimized CS incorporation offers a viable theoretical basis for the development of new TMP-based food formulations.